1. Field of the Invention
The present invention relates generally to the field of supports used to hold a ladder in stable relationship to a slanted or unslanted roof.
2. Description of the Prior Art
Ladder jacks, one example of which is shown in FIGS. 1 and 2, are devices that are used to mount to a ladder for supporting a scaffold or other platform atop the ladder jack. Ladder jacks are commercially available. For example, ladder jacks are available from Werner Co. Corporate Headquarters, 93 Werner Road, Greenville, Pa. 16125.
A typical ladder jack 30 (FIGS. 1 and 2) includes a horizontally extending member 31 pivotally and slideably mounted to the top end of angular member 32. Member 31 is also pivotally mounted to a downwardly extending member 33 having a bottom end pivotally mounted to the bottom of angular member 32. A pair of downwardly opening C-shaped walls 34 and 35 attached to member 33 are slipped over the horizontally extending rungs of a conventional extension ladder 40. A scaffold or platform 41 rests atop and is supported by member 31.
Typically, two ladder jacks are positioned one at each end of scaffold 41 to support the opposite ends thereof and thus, a pair of extension ladders are used with each ladder receiving a ladder jack. FIG. 1 shows one such ladder jack mounted to a ladder and supporting one end of the scaffold. FIG. 2 shows the same ladder jack only with the scaffold removed to illustrate features present atop horizontal member 31. A right angle bracket 43 has its horizontal flange fixedly attached to the distal end 49 of horizontal member 31 and also has a vertically extending portion 44 that extends upwardly from member 31. Member 31 includes a horizontally extending slot 45 with a conventional fastener 47 extending through the slot. A downwardly opening C-shaped clamp 48 is mounted to member 31 by fastener 47 and provides a stop surface for any movement of the scaffold toward the distal end 49 of member 31. A second downwardly opening C-shaped clamp 50 is mounted to the proximal end 51 of member 31 by means of a conventional fastening device that extends through member 31. The mutually facing surfaces of clamps 50 and 48 provide limits for horizontal movement of the platform positioned between clamps 50 and 48. Alternatively, clamps 48 and 50 may be slipped over the edges of scaffold 41 to limit movement of the scaffold. The top end of upright member 33 is pivotally mounted to member 31 with the bottom end of member 33 pivotally mounted to the bottom end of angular member 32.
Slot 53 (FIG. 1) extends along the length of vertical wall portion 54 of member 31 with the top end of angle member 32 having a fastening device 55 that extends through slot 53 allowing the top end 36 of member 32 to be adjusted along the length of the horizontal member 31 thereby adjusting positioning of member 33 enabling walls 34 and 35 to be slipped over the ladder rungs while maintaining the horizontal position of member 31 and the scaffold placed there atop. The fastening device 55 is then tightened to maintain the positions of angle member 32, upright member 33 and horizontal member 31.